1. Technical Field
This invention relates to a Vertical-Cavity Surface-Emitting Laser diode (hereinafter referred to as VCSEL), an optical device, a light irradiation device, a data processing device, a light source, a free space optical communication device, and an optical transmission system.
2. Related Art
As light sources for data communication using an optical fiber or the like or for a data processing device such as a copier, VCSELs have been used, which consume less power and can be easily arranged in two dimensional arrays.
In a VCSEL, a semiconductor layer to be oxidized that includes Al as a constituent element may be selectively oxidized so that current confining and light confining can be concurrently performed. When traverse mode control is performed by such selective oxidation, if the semiconductor layer to be oxidized exists near an active layer, light would be excessively confined, and thus the size of the region to be oxidized should be made equal to or less than about 5 micrometers. As a result, the light output of the VCSEL may be limited, and resulting high resistance may generate heat, which may degrade device property.
In a method proposed to address such disadvantages, the semiconductor layer to be oxidized may be disposed spaced apart from the active layer, and the semiconductor layer to be selectively oxidized may be used as a light confining layer, thereby traverse mode may be controlled.
The present invention aims to provide a VCSEL in which the resistance of a current path may be reduced and traverse mode can be controlled, and provide an optical device, a light irradiation device, a data processing device, a light source, a free space optical communication device and an optical transmission system that uses the VCSEL.